Apparatus for driving off moisture from sugar-cane bagasse



April 21, 1959 s. l. GONZALEZ APPARATUS FOR DRIVING OFF MOISTURE FROMSUGAR-CANE BAGASSE Filed Aug. 28, 1956 r 5 Sheets-Sheet 1 [/v VENTOR.

A TTORNEYJ,

April 21, 1959 s. l. GONZALEZ 2,882,612

I APPARATUS FOR DRIVING OFF MOISTURE FROM SUGAR-CANE BAGASSE Filed Aug.28, 1956 5 Sheets-Sheet 2 gas GOO 000 o g- 000 oocfi ooo 0 ooo 0oo 2000i 000; oooqooo QI RQ figg gl 0 00 c500 000-- QQT 0 O 13 M I vf/ vroxz:'W

ATTORNEYS.

April 21, 1959 s. l. GONZALEZ APPARATUS FOR DRIVING OFF MOISTURE FROMSUGAR-CANE BAGASSE Filed Aug. 28 1956 5 Sheets-Sheet 3 MM Bywa gVEENTORJ ATTORNEYS.

April 1959 s. l; GONZALEZ 2,882,612

APPARATUS FOR DRIVING OFF MOISTURE FROM SUGAR-CANE BAGASSE Filed Aug.28, 1956 5 Sheets-Sheef4 [N VEINTOR:

A TTORNEYSA April 21, 1959 s. l. GONZALEZ 2,332,612

APPARATUS FOR DRIVING OFF MOISTURE FROM SUGAR-CANE BAGASSE 5Sheets-Sheet 5 Filed Aug. 28, 1956 f/VVE/V 702' A TTORNE r iinited ratesPatent APPARATUS FOR DRIVING OFF MGISTURE FROM SUGAR-CANE BAGASSE SantosInclan Gonzalez, Hershey, Cuba Application August 28, 1956, Serial No.606,695

3 Claims. (Cl. 3486)- This invention relates to the utilizationofsugar-cane bagasse as a fuel for the boiler-house furnaces of a sugarfactory, and it has for itsobject to provide a method for driving offmoisture from bagasse with a view to increasing the bagasse calorificvalue when it is burned.

The method of. this invention consists in heating the bagasse as itleaves the mills by means ofthevery combustion gases issuing to theatmosphere through the. fac tory chimney and by means of cold air thatis heated by the combustion gases, allowing the bagasse to fallbygravity through vertical tubes exteriorly heated by com.- bustion gasesand injecting heated air into said tubes to directly contact the fallingbagasse, whereupon the bagasse falling through the lower opening of saidtubes will be rendered completely dry. The result of burning suchbagasse is to remarkably increase water evaporation in the boilers, avery important economy in fuel consumption at the boiler-house. beingthereby attained.

Another object of the invention is to provide an apparatus comprising achamber enclosed in a metal wall casing provided with a heat-insulatinglining, within which are installed several series or groups ofbagassegathering vertical tubes whichv are fed andv discharged by meansof an endless conveyor disposed around said casing and comprising aplurality of rakes at the top portion of the conveyor. which are adaptedto distribute the bagasse from the sugar-cane mills within. thebagassegathering tubes. At the bottom. portion: of the conveyor saidrakes receive the dry bagasse discharged through. the gathering tubesand feed it into an inclined channel which will discharge it intosuitable vehicles that will carry the bagasse to the place where it isto be burned. Within a small box at one end of said casing there isinstalled a series of vertical tubes having their upper ends open to theatmosphere and having connected to their lower ends a ventilator fan sothat heated air will be conducted through a manifold tube and directedto a series of vertical tubes each positioned parallel to eachbagassegathering tube. The vertical tubes extend into the. ba-

gasse-gathering tubes 4 distributing the heated air within.

each bagasse-gathering tube through a thinner perforated tube positionedcentrally to each gathering tube. The lower ends of the perforated tubesterminate a certain height above the open bottom of each gathering tubewherein there is provided a rotatable gate for controlling the fallingrate of dry bagasse, the gates of each three tubes being interconnectedby means of motor-driven gears for controlling the discharge of bagasse.Within the casing there are installed two heaters, namely one heater forheating feed water for the boilers and another heater comprising twoseries of coil tubes disposed lengthwise of the casing. The second namedheated receives water at one end of the casing to be heated andterminates at the other end in a water collector tube provided with acontrolling valve to lead heated crude water to its destination.

The invention is described with reference to the figures of theaccompanying drawings, of which:

Figure l is a top plan view of the apparatus of this invention, showinga casing, divided into two portions by a. longitudinal partition.

Figure 2 is a top planview of a modified form of the invention similarto that of Fig. 1, showing the casing divided into two portions by alongitudinal partition but each portion of the casing being providedwith a double number of bagasse gathering tubes than those illustratedin Fig. 1.

Figure 3 is a longitudinal vertical sectional view through the apparatusof Fig. 1 on line 33 of Fig. 1.

Figure 4 is a vertical cross-sectional view on line 4-4 of Fig. 1.

Figure 5' is a detailed perspective view of three endless conveyor rakesfor feeding bagasse to the bagasse-gathering tubes.

Figure 6 is a detailed perspective view of the conveyor bottom plate atits top portion, showing the inlet openings through which the bagasse isfed into the. three gathering tubes of each group as illustrated in Fig,4.

Fig. 7 is an outer elevational view of an outerly corrugatedbagasse-gathering tube.

Figure 8 is an end view of same.

Figure 9 is an outer elevational view of an outerly corrugated cold airheating tube for injecting hot air into. each bagasse gathering tube.

Figure 1.0 is an end view of same.

The present method of driving off moisture from sugarcane bagasseconsists in heating the bagasse that falls vertically through onegathering tube by means of the combustion gases from the boilerfurnaces, which circulates outside the gathering tube, and also heatingthe ba gasse by means of hot air injected into the bagasse massby'rneans of a thin perforated tube so as to thereby fully dry thebagasse which is discharged from the gathering tube and carried to thefurnaces, and which has a much greater calorific value thanv the bagassefrom the mills, and to obtain an evaporation yield at the boilers thatis far greater than at present obtained by directly burning the bagassefrom the mills, which has a water content ofat. least 60%.

The apparatus for. carrying out the method of this invention consists ofa large casing of rectangular sece tion 1 installed at the locationoccupied by the smoke duct 2 which leads tothe conventional chimney 3from the furnaces 4 and is isolated by means of a gate- 5. Said casing 1is made of steel with an inner heat.- insulating lining and its: innerspace is separated from the smoke duct 2 by aligned longitudinalpartitions 6- and 7 inter-spaced by an opening provided with a gate 8and spaced apart from the ends of the casing throughfree spaces 9 and 10adapted to allow the passage of combustion gases from the furnaces/3.The casing 1. is divided into two portions by two metallic partitions,

one longitudinal partition 11 and another transversal' partition 12 toprovide. a passageway 13 at the end of tition 11 there is' installed ina narrow space a series.

of coil tubes 15 in communication through a valve 16 with a crude watersupply, said tubes 15 joining at'a collector 17 provided with a controlvalve-18 for passing hot. crude water to the desired destination. The

space between both rows of tubes 15 is provided with: a series ofpivotally connected gates 19 operable by a. handle 19' and being open asthe apparatus is started,

said gates beingregulated until. thedraughtwithin the casing 1 is fullynormalized.

As illustrated in Fig. 3 of the drawings, cold air heaters are installedat the ends of the spaces into which the casing has been divided by thelongitudinal partition 11. Each heater comprises a lateral box 20adjacent the casing 1 and enclosing a series of vertical tubes 21 havingouter longitudinal corrugations 22 as shown in Figs. 9 and of thedrawings. Said tubes 21 have their reduced top ends passing across thetop wall of the casing 1 and are open to the atmosphere, whereas thereduced bottom ends of the tubes 21 pass across the bottom wall of thecasing 1 and join a collector 23 which is in communication with aventila tor fan 24 adapted to force hot air into the bagasse mass fromthe mills, as will be explained hereinafter. The spaces between thelongitudinal partition 11 and the longitudinal vertical walls of thecasing are each adapted to contain a series of three bagasse-gatheringtubes 25. These tubes 25 are mounted to extend between the top andbottom walls of the casing 1 and each tube is connected to a commonregister box of frustro-conical shape 26. The gathering tubes shall be3-4 meters long and 75-90 cm. in diameter, and the register boxes shallbe cm. high and of a diameter sufiicient to embrace the inlets andoutlets of all three gathering tubes 25. Each bagasse gathering tube hasan outer longitudinal corrugation 25' and carries at its axial line athin perforated tube 27 ending at a distance from the bottom, and arotatable gate 28 is installed in said space, the axis of all gatesbeing connected by a transversal shaft 29 connected by bevelled gears 30with a longitudinal shaft 31 driven by a Mr H.P. motor having a speedreducer. Each hot air injector tube 27 has its upper end bent to extendthrough the bagasse tube 25 where it communicates with a heater tube 32similarly as the previously mentioned heater tubes 21, all tubes 32joining at a horizontal tube 33 communicating with the ventilator fan 24for drawing in heated air and forcing it through the injector tubes 27.

An endless conveyor is installed about the casing 1 for each group of 3bagasse-gathering tubes, which conveyor comprises two endless chains 34and 36 mounted on sprocket wheels 35 at the corners of the casing, ofwhich one is a motor wheel and the remainder are driven wheels. The linkchains 34 and 36 carry pivotally movable rakes 38 which run on a bottomplate 39 above the entrance of the register box 26 common to each groupof three gathering tubes 25, the bottom plate 39 having three largeopenings 40 corresponding to the tubes 25 of each group to allow thepassage and gravity fall of the bagasse conveyed from the mills throughan inclined channel 41. The rakes 38 are slidable on the bottom plate 39between keepers 43.

The right top corner of the casing 1 has installed thereat a duct 43which may be isolated by means of a gate 44 and affords communicationbetween the easing 1 and an additional chimney 45 having three draughtcontrol ventilators 46 which may be regulated by the boiler operator.The vertical duct 13 situated beyond the vertical partition 12 has arotatable gate 48 which may be opened when it is desired to use theconvection chimney 3 or closed when it is desired to use the additionalchimney 45.

Fig. 2 of the drawings illustrates a modified form of easing 1 havingfour series of banks of bagasse gathering tubes 25, each two seriesbeing separated by the longitudinal partition 11, which modificationshould be adopted for sugar factories of largest production capacity.

The operation of the apparatus is as follows: Moistened bagasse from thesugar-cane mills is discharged through the inclined channel 41 into thespaces between the rakes 38 of the endless conveyor and is distributedby said rakes 38 into the openings 40 of the gravity into three bagassegathering tubes 25 off each group. Since the gathering tubes 25 aresurrounded by the combustion gases from the furnaces 4 which circulatethrough and along the two spaces separated by the longitudinal partion11, moistened bagasse falling along and within the gathering tubes 25 isindirectly heated in falling therethrough and at the same time it isheated directly by hot air injected in the bagasse mass through theperforated tubes 27 into which the air heated in tube heaters 21 is fed,the rate of fall of bagasse through the gathering tubes of each groupbeing controlled by the rotatable gates 28. The result is that thebagasse falling through each lower register box 26 passes into the spacebetween the rakes 38 at the lower portion of the endless conveyor to beconveyed to the inclined channel 42 and thereafter conveyed by means ofvehicles or the like to the bagasse furnaces.

Hot air injected through the perforated tubes 27 into the bagassegathering tubes is driven by ventilator fan 24 through the auxiliaryheaters 32 adjacent the tubes 25, to be passed to the auxiliaryperforated tubes 27, thereby allowing the bagasse to be dried morequickly, the evaporation steam being exhausted at the top portion of thegathering tube.

Otherwise, it would be possible to avoid the use of atmospheric air andthe heaters 21 therefor. For this purpose, hot gases should be taken atthe end of the casing 1 through one or more extractors, after their heathas been utilized to heat bagasse gathering tubes exteriorly, at thevelocity and rate necessary to set the required draught, by closing thegate 48 adjacent the chimney 3, thereby rendering the latter not in use.

The latter procedure in which hot gases from the casing 1 are used, isthe most recommendable, for such gases have a minimum moisture contentand their control is easier.

It is likewise advisable to utilize only the amount of bagasse that isnecessary for combustion, the remainder, which is usually a considerablevolume, to be stored for use as a fuel where necessary.

The result obtained in the application of the apparatus to moistenedbagasse from sugar-cane mills is surprising, because the dry bagassedischarged by the apparatus will have at the most a moisture content of5% and its calorific value will be far more than that of the bagasse atpresent being burned at the furnaces of sugar factories, whereupon theyield in water evaporation in the boilers will reach a maximum, byutilizing the heat of the combustion gases which are produced in thepresent furnaces and which are allowed to freely escape to theatmosphere through the chimney.

The apparatus of this invention may likewise be used 1 to drive offmoisture from the froth obtained from sugar juice clarifiers or from thefilters.

It is obvious that changes may be made in the construction details ofthe casing for the bagasse gathering tubes and of the tubes themselves,without thereby altering the essential character of the invention whichis such as claimed hereinafter.

What I claim is:

1. An apparatus for driving ofi moisture from sugarcane bagasse at sugarfactories having a boiler furnace and a chimney, comprising a heatinsulated metallic casing of rectangular shape arranged adjacent thesmoke duct leading from the furnace to said chimney, a longitudinalpartition in said casing dividing the same interiorly into twocompartments, a series of bagasse conducting tubes arranged verticallyon both sides of said partition in the path of combustion gases from theboiler furnaces, air heater tubes arranged vertically at one end of saidcasing and positioned in the path of the combustion gases from saidfurnaces, conveyor means on said casing for distributing moistenedbagasse from the sugar-cane mills to the upper ends of the verticalbagasse conducting tubes, said conveyor means being arranged to conveybagasse discharged from said bagasse tubes to a discharge opening insaid casing, blower means for drawing heated air through said secondmentioned tubes and injecting the same into the bagasse during itsfalling movement through said vertical bagasse conducting tubes, andducts for leading the combustion gases to a conventional chimney afterthey have yielded their calorific value.

2. An apparatus for driving off moisture from sugarcane bagasse at sugarfactories, including a boiler furnace and a chimney, comprising a heatinsulated metallic casing of rectangular shape mounted adjacent saidchimney for receiving combustion gases from said chimney, a partition insaid casing providing a sinuous passageway for said gases, a series ofvertical bagasse conducting tubes arranged on both sides of saidpartition and extending between the top and bottom walls of said casing,the lower portions of said vertical bagasse conducting tubes beingshaped to provide open register boxes, the passage of the combustiongases being controlled in two opposite directions around the verticalbagasse conducting tubes by means of said partition, gates arranged inthe flow path of said gases for controlling the passage thereof to saidpathway, a hot air perforated injection tube mounted in each verticalconducting tube descending along the center thereof and terminating inspaced relation from the lower end of said conducting tube, groups ofair heating tubes arranged at one end of the casing and in the path ofthe combustion gases, blower means for drawing heated air through saidlast mentioned tubes and forcing it into the injector tubes mountedwithin the vertical bagasse conducting tubes, an endless conveyorarranged on the casing and movable above and below said bagasseconducting tubes, conveyor flights on said conveyor for distributingmoistened bagasse to the upper ends of said bagasse conducting tubes andreceiving the treated bagasse as it is discharged from the lower ends ofsaid tubes.

3. An apparatus for driving off moisture from sugarcane bagasse at sugarfactories, including a boiler furnace and a chimney, comprising a casingof rectangular shape installed at the passageway for the combustiongases from the boiler furnaces into said chimney, said casing being madeof metal and having an inner heat insulating lining, a longitudinallyextending partition in said casing for dividing the same, a crosssection partition adjacent the passage of combustion gases leading tothe chimney, a series of vertical bagasse gathering tubes arranged ingroups of three and mounted to extend through the top and bottom wallsof the casing, register boxes on the upper and lower ends of said tubes,rotatable gates in said tubes for regulating the rate of fall of themoistened bagasse through said vertical bagasse conducting tubes, motormeans for controlling said gates, gearing connecting said motor means tothe gates in said tubes, rotatable gates for controlling the passage ofcombustion gases around said vertical bagasse conducting tubes in twoopposite directions, a perforated injector tube mounted in anddescending along the center of each bagasse conducting tube with itslower end in spaced relation from the lower end of its respective tubes,a series of air tubes at one end of the casing arranged in the path ofthe combustion gases, blower fan means for drawing air after it isheated through said air injection tubes, a water heater arrangedlengthwise of said casing adjacent the longitudinal partition thereof,an endless conveyor installed around the casing having rake flights fordistributing moistened bagasse to the upper register boxes of thevertical bagasse conducting tubes and arranged to receive dried bagassedischarged from the lower register boxes of the bagasse conducting tubesfor conveying said dried bagasse to a discharge point, and a heater forfeed water for boilers which are installed in the duct for the passageof combustion gases to the spaces in the casing occupied by the groupsof vertical bagasse conducting tubes.

References Cited in the file of this patent UNITED STATES PATENTS322,257 Chase et al July 14, 1885 746,822 Gorham Dec. 15, 1903 1,509,280Baker et al. Sept. 23, 1924 1,863,803 Pantenburg .Iune 21, 19322,480,146 Lee Aug. 30, 1949

